"Many Tries" means that a student has attempted the same level at least 10 times and might need some assistance. This is also called a Hurdle on the class Report tab.
You can click the name of the game to open it up in test drive and try it for yourself or work with the student from their screen to have them walk you through what they have tried, asking facilitating questions to help get the student unstuck. For additional information on how to help students visit: Helping Students Who Are Struggling or Stuck
How do you clear the alert?
Alerts will clear once a student has successfully completed the level and at the start of the new school year.